1. Field of the Invention
The present invention relates to a device for the thermal connection of an energy storage and/or a cooling plate a device for the thermal connection of a plurality of cooling fins to a cooling plate, to an energy storage device and to a device for the thermal connection of a fluid.
2. Description of the Background Art
Powerful energy storage devices, such as, for example Li ion or NiMH accumulator batteries or super caps, are used in modern hybrid electric vehicles (HEV) or electric vehicles (EV). Heating occurs with these during the rapid charge and discharge due to resistances in and outside the cells. Temperatures higher than 50° C. permanently damage the energy storage. In order to guarantee the function of the energy storage devices, they must be actively cooled. To this end, the energy storage devices are brought into thermal contact with a cooling plate via cooling fins.
According to the conventional art, cooling fins are attached to the cell outer surfaces in an areal single-sided or double-sided manner. The cooling fins are then brought into contact with the cooling plate. The contact surface to the cooling plate is thereby usually the same as the area of the cooling plate of thickness and length. This transition surface is the thermal bottleneck in all constructions.
Through the one-sided connection of the cooling fin to the cooling plate, a temperature difference is produced above all over the height of the cells. The temperature difference is determined by the cell waste heat and the thickness of the cooling fin or by the size of the transition surface between the cooling fin and the cooling plate. A thick cooling fin reduces the temperature difference.
The cooling fins have to be selected to be very thick particularly with high cells in connection with larger waste heats in order to be able to still maintain the permissible temperature difference in the cell. Thick cooling fins result in a low gravimetric and volumetric energy density of the cooling apparatus. In order to avoid the temperature difference over the cell height, fluid-conveying cooling fins can be attached between the cells. The temperature difference in the cells can be almost avoided thereby.
In the case of the cooling fins flowed through by fluid, disadvantages occur in the gravimetric and volumetric energy density, since due to the production possibilities and the permissible pressure loss in the overall construction, the fin thicknesses and the coolant channels cannot be selected to be as small as desired. Moreover, there is also the problem of tightness in the connections and the uniform distribution of the cooling fluid. Since each fin has to be supplied with cooling fluid, with each fin there is at least one connection that has to be sealed.
FIG. 11 shows an energy storage device according to the conventional art, in which there is a uniform heat transfer between a battery cell and a cooling fin. The energy storage device has a battery cell 102, an electrically insulating thermally conductive film 104a with a uniform contact resistance, a cooling structure 104b, which can be embodied as a heat-conducting cooling fin and a base plate with cooling, e.g., in the form of interior channels. A cell height of the battery is denoted by reference number 108. Furthermore, a base 110 of the cooling fin is shown, which represents a heat-conducting connection by adhesive force or other heat-conducting connection.
FIG. 12 shows an energy storage device according to the conventional art in which there is a uniform heat transfer between cooling fins and cooling plate. The energy storage device has a first battery cell 501, a second battery cell 502 and a third battery cell 503 as well as a cooling plate 106 with cooling, e.g., in the form of interior channels. An electrically insulating thermally conductive film 504a with a uniform contact resistance is arranged, for example, between the cooling plate 106 and the cooling structures of the respective battery cells. Furthermore, a base 110a, a “best efficiency point” 510a and a “worst efficiency point” 510b are shown by way of example.